This invention relates generally to the correction of valvular dysfunction and the localized reorientation of the structural and functional integrity of the distorted ventricular geometry, and, more particularly, to develop an adjustable periventricular ring/ring-like device for control of ischemic mitral regurgitation, and congestive heart disease and the method thereof.
Patients with ischemic heart disease have a wide range of pathological changes. Some of these include ventricular dilatation, dilatation of the mitral annulus, papillary muscle displacement and tethering, choral and papillary infarcts, segmental and global ventricular dysfunction. The mitral valve function and competency rests on the fine geometric and functional integrity of its supporting structures.
When the left ventricle dilates, the papillary muscles are tethered, thus preventing adequate closure of the mitral valve. The left ventricle has two papillary muscles. Both originate from the left ventricular free wall. The anterior papillary muscle is attached to the anterior wall of the left ventricle, close to its lateral border. The posterior papillary muscle originates from the posterior wall, near the junction of the interventricular septum. The mitral valve closure is effected by the apposition of its leaflets. Papillary muscle tethering has been shown to be one of the important mechanisms resulting in mitral valve incompetency, and failure of leaflet apposition.
There is controversy about the role of the myocardial contractility in the preservation of the valve competency. Loss of contractility and dilation of the mitral annulus might also play an important function. In summary, the spatial orientation affects the distribution of the tension effecting leaflet closure.
Previous work that addressed ischemic mitral regurgitation includes:
(a) Revascularization alone (Coronary Artery Bypass Grafting):
Czer et al. documented that revascularization alone does not improve mitral regurgitation. In a study of 2000 patients who underwent coronary artery bypass surgery, uncorrected mitral regurgitation nearly doubled the risk of late death.
(b) Annuloplasty:
Mitral valve annuloplasty addresses the mechanism pf annular dilation as a cause of ischemic mitral regurgitation. It could compensate for papillary muscle tethering to some extent, and improve mitral leaflet coaptation. However, clinical observations suggest that it does not correct for the actual tethering of the leaflets. In additon, annuloplasty techniques involve opening the heart which is more of an invasive approach than the suggested device.
(c) Pericardial restraint independently has been suggested to limit LV size.
(d) Surgical techniques developed by Batiste and Affiori have advocated resection of areas of the ventricle and surgically stitching the valve leaflets together, yet again an invasive procedure.
Other ventricular remodeling techniques and patents have been introduced, such as the acorn device which encircles the heart in global LV dilatation and does not address specific segmental pathology. The acorn device is not directed or fixed with out specifications. It does not provide selectivity of the target points nor adaptability. The fixation and tension are different from our device. Intraoperative observations suggest that force or pressure applied outside papillary muscle could eliminate the mitral regurgitation.
Another device, the myocor, includes a tensor member mechanism that is inserted inside the heart and changes the diameter of the ventricle at that point. This is more invasive than our device. The point of fixation is on the heart versus the sturdier rib cage in our invention.
Surgical methods utilizing alternating deflating balloons around the heart do not provide the precise localized augmentation of function that is required. These methods do not have precise targeting or sturdy fixation. Precise targeting and correction of the stress strain and displacement interactions are specifically important for the intricate geometry of the mitral valve.
Most if not all of these procudures, techniques, or devices have targeted a circumferential change in LV geometry versus a specific regional change in displacement, tension, and force.
It is therefore the object of the present invention to treat mitral regurgitation by directly addressing the disease of the ventricle and supporting structures as the underlying mechanism for the incompetency of the mitral valve in ischemic heart disease or any form of venticular geometric distortion.
It is another object of the present invention to treat segmental dysfunction and optimize global LV efficiency by optimizing the stress, strain displacement interactions. In essence, it could function as a ventricular assist device.
It is another object of the present invention to stabilize the beating heart for other operations when the pressure heads are set on negative suction.
It is a further object of the present invention to apply it on the right ventricle.
The objects set forth,, above as well as further and other objects and advantages of the present invention, are achieved by the embodiments of the invention described hereinbelow.
The present invention related to a device, which could deliver the targeted localized force, tension and displacement changes with a minimally invasive approach. It would prevent inordinate tension placed on the mitral valve or the relative stenosis that could occur with annuloplasty techniques.
The present invention relates more particularly to the restoration of mitra valve competency and compensates for the regional ventricular dysfunction in general and strain induced by papillary muscle tethering. It corrects for the displacement and forces on leaflet closure. An advantage of the localized force and displacement change, a feature of this device, is to avoid coronary flow impedance, minimize damage, and maximize impact.
One feature of the present invention is its stability around the heart, diverting fixation tension, leverage and stress from the heart to the rib cage; therefore delivering force or tension required to the specific point.
For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims.